1. Field of the Invention
This invention relates generally to a printer, and more specifically to a printer having a printing head incorporating a daisy wheel having a central disc portion and a plurality of character stalks radiating therefrom. The invention also concerns the daisy wheel per se.
2. Description of the Prior Art
In a daisy wheel printer, it is necessary, in accordance with character selection by a keyboard, computer or other character selecting means, to move the selected character to an operative position for imprinting of said character by an impacting mechanism such as a hammer. For this purpose the position of the daisy wheel as it rotates must be precisely monitored. One convenient and inexpensive means for providing positional information is to observe the stalks of the daisy wheel, as the latter rotates, with a non-contacting sensor. This sensor produces pulses representing quanitized positional information as to the rotational position of the daisy wheel. However, this sensor only gives relative information about the rotation of the daisy wheel. In order to gain absolute positional information, i.e. to know exactly where any character is and thereby by how much the wheel must be rotated, it is necessary to provide a datum from which to count the pulses produced by the stalk-observing sensor.